[Association between plasma osteopontin level and mild cognitive impairment in patients with type 2 diabetes mellitus].

Objective: To analyze the influencing factors of type 2 diabetes mellitus (T2DM) patients with mild cognitive impairment (MCI), and to explore the association between plasma osteopontin (OPN) levels and MCI. Methods: A retrospective analysis was conducted on the clinical data of 254 patients with T2DM admitted to Zhongda Hospital Affiliated to Southeast University from October 2021 to May 2023. The patients were divided into MCI group (n=106) and normal cognitive function control group (n=148) according to whether they had MCI. Clinical data were collected, cognitive function was assessed using neurological scales and plasma OPN levels were measured by enzyme linked immunosorbent assay. A multivariate logistic regression model was applied to analyze the influencing factors of MCI in T2DM patients. Interaction terms between gender, age, body mass index (BMI), and OPN were established to verify their significance levels. Receiver operating characteristic (ROC) curves were plotted to evaluate the predictive value of OPN for MCI in T2DM patients. The mediation model of OPN-FPG-montreal cognitive assessment(MoCA) was constructed with fasting plasma glucose (FPG) as the mediating variable to test the mediating effect, and the mediating effect percentage was calculated. Results: A total of 254 patients were included, including 162 males and 92 females, with an average age of (61.5±7.5) years old. Compared with the control group, the patients in MCI group were older[63.0(59.0, 69.0) years vs 60.0(54.2, 66.8) years], had a greater proportion of females [(43.4%(46/106) vs 31.1%(46/148)], shorter years of education[12(9, 12) years vs 12(9,15) years], longer duration of diabetes[15.0(8.0, 20.0) years vs 10.0(5.0, 15.0) years], and higher levels of FPG[7.78(6.07, 10.23) mmol/L vs 6.86(5.36, 8.59) mmol/L], insulin resistance index[2.93(2.47, 3.98) vs 2.79(2.27, 3.25)], glycated hemoglobin (HbA1c) [9.24%(7.89%, 10.96%) vs 7.97%(7.00%, 9.45%)], total cholesterol(TC)[(4.51±1.17) mmol/L vs (4.19±0.99) mmol/L], and OPN [11.30(8.68, 12.84) ng/ml vs 9.69(7.82, 11.74) ng/ml] (all P<0.05). The scores of various neuropsychological tests in MCI patients were lower than those in control group with normal cognitive function (all P<0.05). Spearman correlation analysis showed that age(r=-0.212), duration of diabetes mellitus(r=-0.156), duration of hypertension(r=-0.132), FPG(r=-0.207), insulin resistance index(r=-0.171), HbA1c(r=-0.271), OPN(r=-0.238), and total cholesterol (r=-0.125) were negatively correlated with MoCA scores, whereas years of education(r=0.285) were positively correlated with MoCA scores(all P<0.05). Multifactorial logistic regression analysis showed that age, years of education, duration of diabetes mellitus, HbA1c, TC and OPN levels were the influencing factors of T2DM patients with MCI, and the risk of MCI increased by 15% for every 1 ng/ml increase in OPN (OR=1.15, 95%CI: 1.021-1.295, P=0.021), and the relationship was not affected by age, gender and BMI(The interaction effects are all P>0.05). The area under the curve (AUC) of the working curve of subjects with OPN predicting combined MCI in patients with T2DM was 0.612 (95%CI: 0.541-0.682), and the AUC was 0.702 (95%CI: 0.638-0.767) after the combination of HbA1c and OPN. The results of the mediated effect model showed that FPG partially mediated the correlation between OPN and MoCA in T2DM patients, and the mediated effect accounted for 11.34% of the total effect. Conclusions: Plasma OPN level is associated with MCI in patients with T2DM,and the higher the OPN level, the higher the risk of T2DM patients developing MCI.